If you took a giant volcano and deflated it like a fallen soufflé, you would have Yellowstone National Park. The site of an ancient volcano, it is now an enormous valley where the Earth's insides literally ooze, sputter, and explode to the surface. We toured the mud pots, sulfurous steam vents and geysers of the park. Most of the pools have an unbelievably clear blue center as the water is too hot for any organisms to grow and taint the aqua hue. We then entered the Grand Canyon of Yellowstone where the Yellowstone River erodes its way through the mustard and ocher colored rock as it plummets through a series of waterfalls. We winded our way through forest and prairie to the most famous of all National Park attractions - the Old Faithfull geyser. Sure enough, we witnessed its explosive power as it erupted right on schedule, spewing water and steam hundreds of feet into the air - quite impressive. We drove to the south entrance of the park and camped at Lake Lewis (it seems everything around here is named after the intrepid explorers Lewis & Clark - there's Lake Lewis, Clark Fork, Lewiston, and on and on). We quickly got a campfire going and roasted hot dogs for dinner and marshmallows for dessert over the flames - a great way to spend our last night camping! On Wednesday, we drove through Grand Teton National Park and gawked at the impossibly abrupt peaks jutting straight out of the prairie. The Teton Range is unique as there are no foothills to the mountains - plate tectonics just push these granite monsters thousands of feed up over the valley below. Technically, the town is "Jackson" and the valley is "Jackson Hole" ("hole" being an old trapper term for valley). We continued out of Wyoming and cut the corner of Idaho, driving through rolling fields of wheat and potatos. We made it as far as Salt Lake City, Utah and watched the full moon rising over the Wasatch range to the East as we pulled into the hotel for the night.